The goal of this Phase II Competing Continuation research project is to complete the Phase I clinical trial of a new magnetic resonance imaging guided minimally invasive treatment for focal brain tumors. Over the past four years, BioTex has developed the Visualase(r) thermal therapy system for treatment of localized cancers by using temperature-sensitive magnetic resonance imaging (MRI) data to precisely control the delivery of laser energy and the extent of tissue destruction. The current primary target applications for this system are small focal secondary or metastatic tumors in the brain and localized cancer in the prostate. Secondary applications include treatment of metastatic lesions in vertebral bodies, and unresectable liver tumors. Approximately 40,900 primary brain tumors and over 100,000 metastatic brain tumors will be diagnosed this year in the U.S. Additionally, 190,000 American men will be diagnosed with prostate cancer, and over 30,000 will die from the disease. Of the 1.3 million patients who will be diagnosed with cancer this year (excluding nonmelanoma skin cancers), approximately 5-10% will develop problematic secondary metastatic tumors in the spine which will require intervention. In the first year of the proposed study, we will engage in pre-clinical studies and administrative activities required for U.S. Food and Drug Administration (FDA) approval of an investigative device exemption (IDE). In the second and third years, we will conduct a Phase I clinical trial to explore the safety and utility of the Visualase system for treatment of patients will small focal metastatic brain tumors, particularly those which are deep-seated or otherwise inoperable. At the end of this study, we will have explored the clinical feasibility and safety of intracerebral laser therapy for treatment of small focal metastatic lesions, and we will have advanced the Visualase system and components to a feature and production level appropriate for 510(k) pre-market approval. This combination of stereotactic laser thermal therapy with real-time MRI will facilitate an unprecedented integration of the diagnostic and therapeutic environments.